Improvement in guards for door-knobs



HERRMANN AHREND, OF

FFICE PATENT NEWARK, NE W JERSEY.

IMPROVEMENT IN GUARDS FOR DOOR- KNOBS.

Specification forming part of Letters Patent lie-137,400, dated April 1, 1873; application tiled November 22, 1872.

To all whom it may concern:

Be it known that I, HERRMANN AHREND, of Newark, in the county of Essex and State of New Jersey, have invented a new and useful Improvement in Knob-Latches; and I do hereby declare the following to be afull, clear, and exact description thereof, which will enable those skilled in the art to make and use the same, reference being had to the accompanying drawing forming part of this specification, in which drawing- Figure 1 shows my improvement when locked, the cover of the rosette beingremoved to show the invention. Fig. 2 is a similar view when unlocked. Fig. 3 is across-section, taken in the line was of Fig. 1.

Similar letters indicate corresponding parts.

This invention relates to safety or night latches for securing doors, such as wherein the spindle of the door-knob is capable of being locked and prevented from turning, unless the locking mechanism be operated upon by a key constructed for the purpose. The invention consistsin arranging a notched and flanged nut within a rosette, through which passes the spindle of a door-knob, said nut operating in connection with a swinging dog and one or more tumblers, for locking the spindle, as hereinafter specified, said tumblers being actuated from without the rosette, through a hole in its edge, by means of a key provided with bits of suitable shape. With the pivoted dog and tumblers is combined a catch, journaled in the rosette, so that its free end can be made to swing across an opening formed in the rosette, to receive a stud that projects from the cover for the purpose of locking the cover to the rosette. The nut, which is mounted in the center of the rosette to receive the spindle at that point, has on its outer side an extension or flange, which moves in the hollow of the rosette. This flange is notched to receive a projection from a dog, which can be locked by means of spring-tumblers that are actuated from without the rosette, and through a hole in its edge, by means of a key provided with bits of suitable shape. The tail of the dog, when the spindle is locked by it, comes into such a position in relation to the catch that secures the rosette that said catch is locked by it. When the dog is raised from its engagement with the nut, its tail is removed from the catch far enough to allow the catch to be disengaged from the cover of the rosette, its disengagement being accomplished by a pin or key which is pushed through a hole in the edge of the rosette.

In the drawing, the letter A designates a spindle and knob set in a door, and B designates a hollow rosette or box, provided with a removable cover, 0, whose hub or center, where the spindle passes through it, has a flange, D, that covers the set-screw E,by means of which the knob is secured to the spindle. The letter F designates a flanged nut that passes through the center of the rosette, and is kept in place by a notched flange, G, that overlaps the edge of the opening in the rosette. The notch in its flange is marked H, and is designed to receive a spur, I, on the edge of a dog, J, which is pivoted to the row sette at a, and which is provided on its face with a spur, b, that engages notches c on the ends of spring-tumblers T (three in number in this example) that are suitably mounted in I the rosette. The tail (1 of the dog J extends towards a catch, K, which is pivoted in the rosette at e, and whose free end can swing across a hole, f, made through the rosette to receive a vertical stud, L, that projects from the cover 0, as shown in the drawing, one side of the stud L being slotted, as shown, to allow the edge of the catch to engage it, and thereby lock the cover to the rosette, while the extremity of the catch passesinto a notch made for it in a post, M, on the inner surface of the rosette. The back part of the catch K, when it engages the stud of the cover, comes close'to the inner edge of the rosette, and opposite a hole, 9, through which a pin, it, is inserted to push it out of engagement with the stud L when it is desired to remove the cover 0.

It is evident that such disengagement cannot take place while the tail d of the swinging dog J occupies the position shown in Fig. 1; but when the dog is raised out of the notch of the nut its tail is brought to a position which allows the catch to be pushed inward by the pin, so that the cover can be lifted 0d the rosette. that the same movement of the dog which locks the spindle also locks the catch or fast- It will be observed, therefore,

ening of the cover, so that the interior of the rosette cannot be got at without breaking it to pieces. In order to operate the tumblers and the dog, I insert the key N through the hole 0 in the edge of the rosette, and thereby bring the notches of the tumblers into coincidence, and at the same time swing the dog out of engagement with the nut, when the spur on the face of the dog will enter the notches of the tumblers, and hold them back against the tension of their springs. When it is desired to lock the spindle again,I insert the key into the hole P in the edge of the rosette, and push the dog toward the nut and into its notches, when the tumblers are released from the spur of the dog.

The nut F is arranged on the spindle in such a'manner that its notch H will always be opposite the spur of the dogJ when the spindle is at rest.

The rosette is secured to the doorby screws, one of which is seen in Fig. 3, and their heads are seen in Figs. 1 and 2. These screws are of course inaccessible so long as the cover 0 remains in place.

What I claim as new, and desire to secure by Letters Patent, is-

1. The swinging dog J and tumblers T, in combination with the notched nut F, inclosed in the rosette B of a door-knob, substantially as described.

2. The combination of the dog J and tumblers T with the catch K and stud L of the cover of therosette, substantially as described.

This specification signed by me this 4th day of October, 1872.

HERRMANN AHREND. Witnesses:

W. HAUFF, E. F. KASTENHUBER. 

